The Ground Self-Defense Force and police conducted a joint drill Monday in a scenario of armed agents landing in Hokkaido.
Some 40 senior officers of the GSDF's Northern Army and Hokkaido police took part in the exercise.
It is the first time police and the Self-Defense Forces have held a joint exercise, and officials of the two groups said the purpose is to be ready to maintain "public order and security."
The Northern Army began simulated intelligence-gathering on reports that spies armed with rocket launchers and machineguns had landed in Hokkaido, under the premise that police alone could not handle the situation.
The two bodies coordinated their roles, responding to the changing situation by tracing the movements of the intruders and subduing them, as well as guarding important installations, including vital infrastructure, and evacuating residents, the officials said.
The drill was held in line with the December 2000 revision of an accord between the SDF and police on how to work together to ensure public safety. Since then, situations involving "terrorist activities by armed agents" have been added to the accord.
The agreement, which earlier presupposed cooperation in incidents such as riots, was revised to expand the scope of situations warranting cooperation following revelations of North Korean spy ships intruding into Japanese waters and other incidents.
Senior prefectural police officers from throughout Japan observed the drill and are expected to consider conducting similar training with GSDF units in their areas, the officials said.